       #calc {
            background: #2371d3;
            margin: auto;
            padding: 25px;
            width: 100%;
            height: 100%;
            font-size: 100px;
            border-spacing: 0;
        }
        
        #calc td {
            text-align: center;
            width: 20%;
            border: 5px solid #fff;
        }
        
        #ioput {
            text-align: right !important;
            background-color: #fff;
        }